The present invention refers to a method for preventing plugging of a continuous-reaction channel-system caused by a by-product of a continuous reaction being carried out in said channel-system, and a micro-reactor supporting the continuous-reaction channel-system for carrying out the method.
In micro-reactor continuous-reaction technology, a micro-reactor is continuously passed through by various chemical substances including a plurality of reactants (educts) flowing into the micro-reactor and reacting therein to form a product flowing out of the micro-reactor. Such a micro-reactor is disclosed, for example, in EP1 839 739 A1 of the same applicant. In some of these chemical reactions like metalation reactions where a hydrogen-metal or a halogen-metal exchange takes place, water present within the channel-system may react with one or more of the chemical substances, resulting in a precipitate plugging the channels. The local probability of such plugging to occur is not equal throughout the micro-reactor, but is highest at what are called hereafter plugging-susceptible areas which are confluence and mixing areas where the various reactants come together, are mixed and react with each other.
It should be noted that because even a moderate plugging results in an increased pressure compared to using dry feeds, and consequently in a possible decrease in yield, only dry feeds/solvents are used, which is very cost-intensive because the drying procedures applied are very involved. For example, several ethers such as diethyl ether, methyl tertiary butyl ether (MTBE), tetrahydrofuran (THF) or solvents such as dimethyl sulfoxide (DMSO) are very hard—and therefore expensive—to completely separate from traces of water. In addition, drying is not in all cases without any problems. For example, the above reaction (1) is known to proceed very violently, and other substances like organic nitrates or azides may even be explosive. The reference to organic nitrates or azides is only to give a general example that some substances can not be dried because the drying procedure is dangerous. Therefore, also from this perspective, a method is needed that goes without drying.